PATCH: add SPU -mfixed-range option

[Ben Elliston <bje at au1 dot ibm dot com>]

This patch implements -mfixed-range for the SPU.
Okay for mainline?


2006-12-12  Sa Liu  <saliu@de.ibm.com>
            Ben Elliston  <bje@au.ibm.com>

        * config/spu/spu.opt (mfixed-range): New option.
        * config/spu/spu.h (spu_fixed_range_string): Declare.
        * config/spu/spu.c (spu_override_options): Handle -mfixed-range.
        (fix_range): New function.
        * doc/invoke.texi (SPU Options): Document -mfixed-range.


Index: config/spu/spu.opt
===================================================================
--- config/spu/spu.opt	(revision 119761)
+++ config/spu/spu.opt	(working copy)
@@ -52,3 +52,6 @@ mlarge-mem
 Target Report RejectNegative Mask(LARGE_MEM)
 Generate code for 32 bit addressing
 
+mfixed-range=
+Target RejectNegative Joined Var(spu_fixed_range_string)
+Specify range of registers to make fixed
Index: config/spu/spu.h
===================================================================
--- config/spu/spu.h	(revision 119761)
+++ config/spu/spu.h	(working copy)
@@ -24,6 +24,7 @@
 #define OVERRIDE_OPTIONS spu_override_options()
 
 extern int target_flags;
+extern const char *spu_fixed_range_string;
 
 /* Default target_flags if no switches specified.  */
 #ifndef TARGET_DEFAULT
Index: config/spu/spu.c
===================================================================
--- config/spu/spu.c	(revision 119761)
+++ config/spu/spu.c	(working copy)
@@ -128,6 +128,7 @@ static unsigned char spu_rtx_costs (rtx 
 static unsigned char spu_function_ok_for_sibcall (tree decl, tree exp);
 static void spu_init_libfuncs (void);
 static bool spu_return_in_memory (tree type, tree fntype);
+static void fix_range (const char *);
 
 extern const char *reg_names[];
 rtx spu_compare_op0, spu_compare_op1;
@@ -264,6 +265,9 @@ spu_override_options (void)
 
   if (align_functions < 8)
     align_functions = 8;
+
+  if (spu_fixed_range_string)
+    fix_range (spu_fixed_range_string);
 }
 
 /* Handle an attribute requiring a FUNCTION_DECL; arguments as in
@@ -3574,6 +3578,68 @@ mem_is_padded_component_ref (rtx x)
   return 0;
 }
 
+/* Parse the -mfixed-range= option string.  */
+static void
+fix_range (const char *const_str)
+{
+  int i, first, last;
+  char *str, *dash, *comma;
+  
+  /* str must be of the form REG1'-'REG2{,REG1'-'REG} where REG1 and
+     REG2 are either register names or register numbers.  The effect
+     of this option is to mark the registers in the range from REG1 to
+     REG2 as ``fixed'' so they won't be used by the compiler.  */
+  
+  i = strlen (const_str);
+  str = (char *) alloca (i + 1);
+  memcpy (str, const_str, i + 1);
+  
+  while (1)
+    {
+      dash = strchr (str, '-');
+      if (!dash)
+	{
+	  warning (0, "value of -mfixed-range must have form REG1-REG2");
+	  return;
+	}
+      *dash = '\0';
+      comma = strchr (dash + 1, ',');
+      if (comma)
+	*comma = '\0';
+      
+      first = decode_reg_name (str);
+      if (first < 0)
+	{
+	  warning (0, "unknown register name: %s", str);
+	  return;
+	}
+      
+      last = decode_reg_name (dash + 1);
+      if (last < 0)
+	{
+	  warning (0, "unknown register name: %s", dash + 1);
+	  return;
+	}
+      
+      *dash = '-';
+      
+      if (first > last)
+	{
+	  warning (0, "%s-%s is an empty range", str, dash + 1);
+	  return;
+	}
+      
+      for (i = first; i <= last; ++i)
+	fixed_regs[i] = call_used_regs[i] = 1;
+
+      if (!comma)
+	break;
+
+      *comma = ',';
+      str = comma + 1;
+    }
+}
+
 int
 spu_valid_move (rtx * ops)
 {
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi	(revision 119761)
+++ doc/invoke.texi	(working copy)
@@ -733,7 +733,8 @@ See RS/6000 and PowerPC Options.
 @gccoptlist{-mwarn-reloc -merror-reloc @gol
 -msafe-dma -munsafe-dma @gol
 -mbranch-hints @gol
--msmall-mem -mlarge-mem -mstdmain}
+-msmall-mem -mlarge-mem -mstdmain @gol
+-mfixed-range=@var{register-range}}
 
 @emph{System V Options}
 @gccoptlist{-Qy  -Qn  -YP,@var{paths}  -Ym,@var{dir}}
@@ -12909,6 +12910,14 @@ With @option{-mstdmain}, GCC will link y
 code that assumes a C99-style interface to @code{main}, including a
 local copy of @code{argv} strings.
 
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator can not use.  This is
+useful when compiling kernel code.  A register range is specified as
+two registers separated by a dash.  Multiple register ranges can be
+specified separated by a comma.
+
 @end table
 
 @node System V Options